Which endoleak type occurs when the graft material is too porous?

Which endoleak type occurs when the graft material is too porous?

• A. Type I
• B. Type II
• C. Type III
• D. Type IV

Answer: (D)

Blood seeping directly through the graft fabric into the aneurysm sac is due to the material’s porosity, so the endoleak type here is the one caused by graft porosity. When the graft is sufficiently porous, blood can pass through the fabric itself into the sac, producing a leak that isn’t from a misplaced seal or a disconnected component. This tends to be an early phenomenon after implantation and is less common with modern low-porosity devices, which is why it’s often highlighted as the porous-material endoleak. For context, other endoleak types stem from different mechanisms: a leak at the proximal or distal seal points around the graft causes direct flow around the graft (endoleak type I); retrograde flow into the sac from collateral arteries like the inferior mesenteric or lumbar arteries causes type II; and a defect in the graft fabric or a disconnection between modular components allows blood to pass through the graft or between pieces (type III). The key distinction here is that the leak comes through the graft fabric itself, not around it or through collateral vessels.

Blood seeping directly through the graft fabric into the aneurysm sac is due to the material’s porosity, so the endoleak type here is the one caused by graft porosity. When the graft is sufficiently porous, blood can pass through the fabric itself into the sac, producing a leak that isn’t from a misplaced seal or a disconnected component. This tends to be an early phenomenon after implantation and is less common with modern low-porosity devices, which is why it’s often highlighted as the porous-material endoleak.

For context, other endoleak types stem from different mechanisms: a leak at the proximal or distal seal points around the graft causes direct flow around the graft (endoleak type I); retrograde flow into the sac from collateral arteries like the inferior mesenteric or lumbar arteries causes type II; and a defect in the graft fabric or a disconnection between modular components allows blood to pass through the graft or between pieces (type III). The key distinction here is that the leak comes through the graft fabric itself, not around it or through collateral vessels.